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Journal of Postgraduate Medicine, Vol. 50, No. 1, January-March, 2004, pp. 79-80 Letter To Editor A case of cor triatriatum with pregnancy: An anaesthetic challenge Mathew PJ, Subramaniam R, Rawat RS, Kulkarni A Department of Anaesthesia and Critical Care, All India Institute of Medical Sciences, New Delhi - 110 029 Code Number: jp04009 Sir, A 28-year-old fifth gravida underwent emergency caesarean section at 35 weeks gestation due to severe pre-eclampsia. At 25 weeks gestation she was diagnosed as having cor triatriatum with ostium secundum atrial septal defect. Pregnancy-induced hypertension (PIH) was diagnosed at 26 weeks; she received alpha-methyldopa 250 mg 6 hourly until delivery. Pre-anaesthetic evaluation revealed a 50 kg female with no obvious dyspnoea. Central cyanosis was present; heart rate was 136/min and blood pressure 130/90 mmHg. Her renal and liver function tests and coagulation profile were normal. 2D echocardiography with Doppler showed severe pulmonary arterial and venous hypertension with a left ventricular ejection fraction of 55%. Anti-aspiration prophylaxis and infective endocarditis prophylaxis were administered. Continuous ECG, non-invasive blood pressure and pulse oximetry (SpO2) in addition to central venous pressure (CVP) were monitored. Baseline CVP was 10 cm of saline and SpO2 on room air was 82%; it increased to 90-92% on pre-oxygenation. Anaesthesia was induced by modified rapid sequence technique with fentanyl 100µg, thiopentone 150 mg, lignocaine 80 mg and suxamethonium 100 mg; the trachea was intubated with a 7.0 mm endotracheal tube. Isoflurane 1% with vecuronium maintained anaesthesia. A 1.72 kg male baby was delivered with Apgar score seven and eight at one and five minutes, respectively. Uterine contraction was augmented with oxytocin 15 units i.v. At this point, ECG showed occasional ventricular ectopics, however there was no haemodynamic instability. Intraoperative haemodynamic parameters remained within the acceptable range. SpO2 was 90-91% on 100% inspired oxygen. CVP varied between 10 and 17 cm saline. At the end of surgery, residual neuromuscular blockade was reversed with neostigmine and atropine and the trachea extubated. During surgery, a total of 250 ml of lactated Ringer′s solution was administered and the urine output was 100 ml. The patient was monitored in an intensive care unit for 24 hours; there was no recurrence of ventricular ectopics. She was discharged on the fifth postoperative day. Cor triatriatum is a rare cardiac anomaly, wherein the left atrium is divided into two chambers by an abnormal oblique fibromuscular membrane.[1] It imposes great difficulties in anaesthetic management.[2] The choice of anaesthesia in our patient was additionally complicated due to the presence of two conditions altering physiology viz. pregnancy and PIH. PIH is marked by contracted intravascular volume, increased systemic and pulmonary vascular resistance, increased afterload on the left ventricle (LV) and decreased colloid oncotic pressure, thereby predisposing to pulmonary oedema. Owing to pulmonary venous obstruction, pressure in the pulmonary capillary bed, pulmonary artery and right ventricle is increased. Though the pressure in the left ventricle is normal, the systemic cardiac output is low or borderline due to decreased preload. When the two conditions coexist, the left ventricle has increased afterload and decreased preload-a combination that tends to worsen the cardiac output. Prevention of tachycardia and atrial dysrrhythmias is vital to ensure adequate LV preloading along with avoiding sudden decrease in systemic vascular resistance. Digoxin may be considered to optimise the patient. As there is a combination of low intravascular oncotic pressure due to PIH and increased intravascular hydrostatic pressure due to cor triatriatum, the pulmonary capillary bed becomes extremely prone to pulmonary oedema. A pulmonary vasodilator may help in this situation by facilitating a decrease in the intravascular hydrostatic pressure. It is also important to avoid an increase in the central blood volume by extraneous administration of fluids. General anaesthesia was chosen in our patient as it permitted haemodynamic manipulation based on the patient′s response. As thiopentone in larger doses can decrease systemic vascular resistance and cardiac output undesirably, fentanyl was used to decrease heart rate and reduce the induction dose of thiopentone. Although nitrous oxide (N2O) is a usual accompaniment to inhalational anaesthesia, its use is limited in conditions of preexisting hypoxaemia. Graded epidural anaesthesia is gaining a foothold as the preferred mode of anaesthesia in mitral stenosis wherein pathophysiology is similar to cortriatriatum.[3],[4] The same technique is likely to be useful in cor triatriatum as well. However, there is no evidence to support or refute this. A subarachnoid block may produce undesirable hypotension or bradycardia. Our patient was predisposed to pulmonary oedema for several reasons viz. underlying cardiac anomaly, fluid administration during surgery and autotranfusion due to uterine contraction following delivery.[5] Fluid administration guided by continuous monitoring of CVP prevented pulmonary oedema. Pulmonary capillary wedge pressure monitoring is ideal in such situations. References
Copyright 2004 - Journal of Postgraduate Medicine |
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